1. Field of the Invention
This invention relates generally to duct networks, and specifically to seal systems used in providing an airtight joint between the ends of adjacent duct sections.
2. Discussion of the Related Art
This invention relates to a seal system for providing an airtight joint between two duct sections. More specifically, the invention encompasses a seal attached to rectangular frames which connect the duct sections.
Prior art duct systems have utilized linear strips of adhesive back sealing material that must be crimped at the corners. The crimping action produces voids through which air may escape. In large duct networks, large volumes of air are moved through the network under high pressures. A void between duct sections, even if small to begin with, may develop into a larger void, potentially halting the operation of the entire network by depressurizing the duct network.
The excess bunching of the sealing gasket also obstructs the airway through the duct. Due to the seal being forced into a shape it is not designed for, the excess portions of the sealing gasket around corners may obstruct the airflow in the duct. At high pressures, these gasket pieces may break loose, and create further problems within the duct.
Another type of sealing gasket is disclosed in the prior art. Arnoldt U.S. Pat. No. 4,662,661 discloses a flange type duct assembly and seal arrangement. A seal is shown in the drawings as an endless rectangular loop. Arnoldt U.S. Pat. No. 5,022,688 again shows a continuous one-piece seal mounted between the flanges.
These sealing gaskets are cut into the rectangular shape desired, but are difficult to install. There is considerable waste of material, and the gasket is difficult to affix to the frame due to its awkward shape. If a mistake is made in affixing the gasket, it must be discarded and the process restarted.